Recently, satellite (BS) digital broadcast using a broadcasting satellite has been discussed. BS digital broadcast enables multichannel broadcasting by applying a compression technique using MPEG (Moving Picture Experts Group) 2. Since multichannel broadcasting significantly increases the number of programs to be broadcasted at a time, selecting a program to view becomes difficult.
To cope with this, in BS digital broadcast, an EPG (Electronic Program Guide) function is added for selecting a program electronically by displaying a program list on a screen. To realize this EPG function, in BS digital broadcast, a SIT (Selection Information Table) stream is multiplexed together with a video stream and a voice stream, and data called EIT (Event Information Table) is inserted into this SIT stream. The EIT data is program guide data of each broadcasting and introduction data of a program itself, indicating the correspondence of programs contained in each service and information related to each program.
A digital broadcast receiver which supports BS digital broadcast [hereinafter also referred to as set top box (STB)] is generally designed to prepare a program list based on received EIT data and to be provided with a program guide display generating unit for displaying the program guide data on the screen.
In such a digital broadcast receiver, received BS digital broadcast signals are demodulated after being selected by a tuner, and then, given error correction. When a broadcasting station scrambles broadcast signals to prevent non-subscribers from viewing, only programs allowed to be viewed are de-scrambled in units of packets out of streams which have undergone error correction.
As described above, digital satellite broadcast has become multichannel broadcasting and has EPG data multiplexed therein. A viewer selects a program using EPG data. Broadcast signals de-scrambled are supplied to a demultiplexer of the digital broadcast receiver. This demultiplexer fetches image and voice data and EPG data for one channel from the descrambled digital broadcast signals.
According to the MPEG2 standard, data can be transmitted in transport stream (TS) which has considered transmission of a plurality of programs in one stream. A transport stream is composed of fixed-length packets (transport packet), and contains video data, voice data and other data.
The output of a demultiplexer is a transport stream like this. A transport stream selected by a viewer is supplied to each decoder and a stream of one program (PS) is extracted. This stream is converted into data corresponding to a display and supplied to a television receiver, making a program viewable.
It is possible to make a digital recording unit, such as a DVCR (digital video tape recorder), record only one predetermined program contained in a received stream. To do this, for an interface between a digital broadcast receiver and a digital recording unit, for example, an IEEE 1394 can be used.
The IEEE 1394 standard is a low-cost peripheral interface suitable for multimedia use. The IEEE 1394 is capable of multiplex transfer of a plurality of channels and also has an isochronous transferring function which assures the transfer of video and voice data within a given time (125 .mu.sec.).
A transport stream from a demultiplexer containing a program designated by a viewer is converted into an isochronous packet of IEEE 1394 and transmitted to a digital recording unit. At the digital recording unit, this isochronous packet is converted back into the original transport stream in the MPEG2 standard and recorded.
To view a recorded program, a transport stream reproduced from a digital recording unit is converted into an isochronous packet of IEEE 1394 and transmitted to a digital broadcast receiver. The digital broadcast receiver converts it back into the original transport stream and supplies this transport stream to a decoder. Reproduced images are viewed in this manner.
EPG is also used for recording digital broadcast signals. That is, program guide information is prepared corresponding to EPG contained in a received signal, a screen display is given based on this program guide information, and the user designates a program desired to record out of the programs displayed on the screen. An STB detects the program ID corresponding to the user's designation, converts the only transport stream containing a program with the corresponding program ID into an isochronous packet and supplies it to a digital VTR.
As an AV/C command for controlling units is specified in IEEE 1394, a method has been considered for enabling automatic video recording using a digital VTR by transmitting a video recording command in this AV/C command to the digital VTR.
A proposal for video recording using such a program guide list is disclosed in the Published Unexamined Patent Application No. 9-284664 (No. 284664/1997).
However, a problem was that no consideration was made about a device for displaying data related to programs, which have been recorded on a recording medium by a recording unit such as a digital VTR, on a screen using a GUI (Graphical User Interface).
An apparatus has been devised so that it reads data from MIC and gives a GUI display at the time when a cassette is inserted, by mounting a cassette memory called MIC in a digital VTR cassette and storing in this cassette memory video recording information on a cassette tape. Standards on such MIC are specified in "Specification of consumer-use Digital VCRs" (Bluebook). Nevertheless, even in this case, the operation for recording contents of a cassette tape in the MIC is very complicated.
This problem arises because, though it is possible to record on a magnetic tape a transport stream containing a program designated by a user out of digital broadcast signals, it is impossible to give a GUI display of data related to recorded programs without complicated operation.
Accordingly, an object of the present invention is to provide an apparatus and method of displaying recorded contents that enable an automatic display of recorded contents of a recording medium, which records transport streams obtained from digital broadcast signals, without requiring any complicated operation.